Purchase this article with an account.
Azmir Ahmad, Ai-Hong Chen; Near work-induced transient myopia after short near work duration among Malay adults. Invest. Ophthalmol. Vis. Sci. 2016;57(12):3962.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Short near work duration could also cause near induced transient myopia (NITM) even though NITM was more prominent after prolonged near work. NITM from short near work duration had been investigated previously among Caucasian, Chinese and recently Indian, either among children or young adults. This study investigated the effect of short near work duration on NITM among Malay adults. It was to determine the NITM between non-presbyopic and presbyopic adults, in order to understand NITM occurrence during adulthood.
Twenty three subjects participated in this study with 14 individuals were non-presbyopic adults and 9 individuals were presbyopic adults. Presbyopia were defined based on reduced age-expected accommodative amplitude and requirement for near addition visual correction. The objective distance refractive status was measured with the Grand Seiko WAM-5500 open-field autorefractor, before and after five minutes of near work. All subjects read off a near reading material at 25 cm under binocular viewing conditions. They are continuously instructed to keep clear of the near target at all time. The pre- and post-refractive status measurements was done on right eye. NITM was determined as the difference between both distance refraction statuses which was indicated as initial magnitude of post-task refractive shift.
Non-presbyopic adults demonstrated an initial post-task myopic shift with mean and standard deviation of 0.37 ± 0.31 D, whereas presbyopic adults demonstrated smaller myopic shift with mean and standard deviation of 0.15 D ± 0.09 D. There was a statistically significant difference in the NITM between non-presbyopic and presbyopic adults after short duration of near work (Mann-Whitney U test, U = 105.500, p < 0.05).
Malay non-presbyopic adults demonstrated similar initial magnitude level of post-task refractive shift as other ethnics found in previous researches. The NITM still occurred after short near work duration even among presbyopic adults. The magnitude of the NITM was higher in non-presbyopic adults compared to presbyopic adults for five minute near work duration. The physiological difference between non-presbyopic and presbyopic adults could explain the difference in NITM magnitude between these two groups.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
This PDF is available to Subscribers Only